Surface joints must be placed within the tiled surface regardless of substrate conditions. They provide stress relief from movements in the tile field due to thermal and moisture expansion/contraction and loading. Schluter-DILEX-AKWS is a prefabricated, maintenance-free surface movement joint profile. It features trapezoid-perforated anchoring legs, made of aluminum, which are secured in the mortar bond coat and provide edge protection for adjacent tiles. Dilex-AKWS is sold per 8' piece. Height and color selection is needed for this item.